Japanese Patent Application Publication No. 2005-116963 discloses a switching device having a semiconductor substrate, an upper surface of which is connected to a heat sink block by soldering.
Further, Japanese Patent Application Publication No. 2015-225872 discloses a switching device having a trench that extends in a mesh shape in an upper surface of a semiconductor substrate. An inner surface of the trench is covered with a gate insulating film. A gate electrode is disposed inside the trench. An interlayer insulating film covers the upper surface of the semiconductor substrate and the gate electrode. A contact hole is provided in the interlayer insulating film above each of portions surrounded by the trench (hereinafter referred to as cell regions) in the semiconductor substrate. An upper electrode covers the interlayer insulating film, and is in contact with the semiconductor substrate in the contact holes. Each cell region includes a first region (emitter region) of a first conductivity type (n-type), and a body region of a second conductivity type (p-type). Each of the first regions is in contact with the upper electrode and the gate insulating film. The body region is in contact with the upper electrode, and is in contact with the gate insulating film below the first regions. Further, the semiconductor substrate includes a second region (drift region) of the first conductivity type. The second region is in contact with the gate insulating film below the body region, and is separated from the first regions by the body region. In this switching device, when a potential of the gate electrode is controlled to a predetermined potential, channels are formed in the body region. The first regions and the second region are electrically connected by the channels. Accordingly, a current flows between the first regions and the second region.